1. Field of the Invention
The present invention relates to faucets, and, more particularly, to electronic activation systems for faucets.
2. Description of the Related Art
The state of the art in electronic activation of plumbing faucets utilizes infrared (IR) sensors to determine whether a user is placing his hands or some object such as dishes under the spout. The sensor is typically directed to the general area under the spout. If the sensor determines that the user is placing his hands or some object under the faucet, then a controller turns on a flow of water or some other liquid to the spout. When the IR sensor no longer senses the presence of the hand or object under the spout, then the controller turns off the flow of liquid to the spout.
IR sensors typically include an emitter for emitting IR energy, and a receiver for receiving the IR energy after it has been reflected by some object in the path of the emitted IR energy. Known IR sensors for electronically activating faucets are intensity-based in that the sensors detect the presence of a hand or object under the spout based upon an intensity, magnitude or strength of the reflected IR energy received by the receiver. Generally, the greater the intensity of the reflected energy, the more likely it is that a hand or object has been placed under the spout.
A problem with intensity-based IR sensors is that they cannot easily discriminate between various types of scenarios that may occur in the proximity of a sink. For example, intensity-based IR sensors cannot easily discriminate between a hand entering the sink bowl, the water stream, the water stream with hands actively washing in the stream, and static situations such as a pot placed in the sink bowl. Because of this inability to discriminate, the water stream is not always turned on or off when appropriate.
What is needed in the art is a sensor system that can more easily discriminate between different types of static and dynamic situations in the vicinity of a sink so that the flow of water through the spout may be more accurately controlled.